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What you are describing is commonly known as "false bass".  
Hi John

What you are describing is commonly known as "false bass".  The fact is that while there is nothing actually generating these bass frequencies, they are in the air as if there was a source for them.  Say you play a 16 foot C on an organ, (32hz).  There will be harmonics of 64hz, 96hz, 128hz, 160hz, 192hz, 224hz, 256hz, etc., (some of these notes sound very ugly when instruments like natural horns play them).  Now lets say your system has a LF limit of 30hz.  If you play a 32 foot C, (16hz), your system won't reproduce the fundamental but it will reproduce the first harmonic, 32hz and the rest of the harmonics.  The reason you can hear the missing fundamental and recognize that this is a 32 foot note and not a 16 foot note is the presence of the second harmonic, 48hz, (a G), and all subsequent harmonics with 16hz intervals.  The 48hz harmonic and the 32hz harmonic will combine to produce a 16hz resultant.  Pipe organs utilize this phenomenon to
 produce a 32 foot stop when there are actually no 32 foot pipes.  It is easy to experienc this if you have a piano.  Just play a low C on the piano, then play the same C and the G above it at the same time, it will sound like you are playing a C an octave lower than the one you're playing.  If you are playing orchestral recordings, they will sound to have lower bass than your system is capable of because of all this harmonic inter-action.

db



On Thursday, February 20, 2014 12:18:47 PM, John Haley <[log in to unmask]> wrote:
 
Something to keep in mind on the topic of bass and small drivers is that
>sometimes what you are hearing for deep bass tones is really the first
>harmonic an octave higher, which is often strong and can sometimes "mask"
>as the real thing where it is reproduced strongly but the deep fundamental
>tone is actually missing.  Our ears can be fooled into thinking that the
>real bottom tone is there.
>
>For me, nothing compares to a real subwoofer.  For many popular small
>speaker systems, what they are calling the subwoofer is really the woofer.
>The other great benefit of using a real sub, which I think still pertains
>in today's world, is that whatever driver is handling the midrange will
>often perform with a lot more clarity if that same driver does not have to
>move in and out a inch or so to produce the lower tones, while at the same
>time struggling to produce the much shorter wavelengths of midrange tones.
>
>As Tom said, bass tones can be very directional, but our sense of where the
>bass tones are coming from can be largely determined by their harmonics,
>including those generated by the attack of the note.  These harmonics are
>often high enough to be directional.  They ought to be picked up by the L
>and R speakers if reasonably full range.  I don't know what happens when it
>all passes thru a bass-management stage of a modern A-V amp.
>
>Best,
>John Haley
>
>
>
>
>
>On Thu, Feb 20, 2014 at 10:58 AM, Frank Strauss <[log in to unmask]> wrote:
>
>> Hi Tom-In response to what David said about bass drums not having a
>> definite pitch, I can tell you from the experience of playing in the drum
>> corps of a bagpipe band, that bass drums, as well as tenor and snare drums
>> most certainly have pitches, and much time is spent in the very good bands
>> with harmonizing the drum corps with the pipe corps.  This isn't going to
>> help you, because it is hopelessly out of production, but I use an Altec
>> Lansing ACS45.1 powered computer speaker system.  It has a right and left
>> speaker and a sub woofer that sits under the desk.  It sounds very nice to
>> my ears.  I have used it for PP shows and it fills a room nicely, and
>> people comment on the sound quality.  It makes sitting at the computer much
>> more pleasant.  It was succeeded by ACS340, which is around, but also out
>> of production, I think.  I bought a Klipsch G 17 Air, to use with a
>> laptop.  Amazon has it for $204, and they say it has a list of $549.  It is
>> quite an awful little unit.  The only thing nice about it is that it's
>> bluetooth.  No bass, no separation, and very volume limited.
>>
>>
>>
>>
>>
>> --
>> Frank B Strauss, DMD
>>
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